The phrase the right hand does not know what the left hand is doing and variants express unawareness, or (deliberate) ignorance, of one’s own activities.

This phrase is now mainly used to convey that there is a state of confusion within a group or organisation.

But, in early use, it was an injunction to be discreet in doing good. It is an allusion to Jesus’s Sermon on the Mount. In the King James Version (1611), the gospel of Matthew, 6, is:

1 Take heede that ye doe not your almes before men, to bee seene of them: otherwise yee haue no reward of your Father which is in heauen.
2 Therefore, when thou doest thine almes, doe not sound a trumpet before thee, as the hypocrites doe, in the synagogues, and in the streetes, that they may haue glory of men. Verily, I say unto you, They haue their reward.
3 But when thou doest almes, let not thy left hand know, what thy right hand doeth:
4 That thine almes may bee in secret: And thy Father which seeth in secret, himselfe shall reward thee openly.

In A Funerall Elegie, upon the death of the Earle of Holdernesse (1626), John Taylor (1578-1653), the ‘Water Poet’, wrote:

True Charity belov’d with him did live,
And (ts* the poore) his Glory was to give.
Yet was his bounty from the world so hid;
His right hand knew not what his left hand did.
(* ts = towards?)

The first known use of the phrase in its transferred sense is in Ascanius or, The Young Adventurer. A True History (1779 edition) by the English journal editor, publisher and author Ralph Griffiths (circa 1720-1803):

Now the people of Dumfries having heard and believed, that William had defeated the rebels near Lancaster they waxed [= became] stubborn, and kept a guard, day and night, and sought out all manner of ways to kill and destroy their country-men.
But as soon as four thousand of the rebels appeared in a body, the inhabitants were all stricken with amazement, insomuch that no man’s right hand knew what his left did; for behold then they found it to be a false report, and dreaded the evil that would befal [sic] them.

And, in Nimrod: A Discourse on Certain Passages of History and Fable (1829), the English antiquary Algernon Herbert (1792-1855) wrote:

The works of secrecy are not more absurd and terrible than they are complicated; the left hand does not know what the right is executing, and neither can tell what the head is planning.